Titanium Dioxide: Structure, Impact, and Toxicity

Abstract

Titanium dioxide, first manufactured a century ago, is significant in industry due to its chemical inertness, low cost, and availability. The white mineral has a wide range of applications in photocatalysis, in the pharmaceutical industry, and in food processing sectors. Its practical uses stem from its dual feature to act as both a semiconductor and light scatterer. Optical performance is therefore of relevance in understanding how titanium dioxide impacts these industries. Recent breakthroughs are summarised herein, focusing on whether restructuring the surface properties of titanium dioxide either enhances or inhibits its reactivity, depending on the required application. Its recent exposure as a potential carcinogen to humans has been linked to controversies around titanium dioxide’s toxicity; this is discussed by illustrating discrepancies between experimental protocols of toxicity assays and their results. In all, it is important to review the latest achievements in fast-growing industries where titanium dioxide prevails, while keeping in mind insights into its disputed toxicity.

Photocatalyzed Production of Urea as a Hydrogen–Storage Material by TiO2–Based Materials

“…In turn, metastable anatase and brookite structures can be thermally restructured into stable rutile. Although the rutile crystal phase has the highest structural stability [50], it is hard to find and is a challenge for industrial manufacturing [51].…”

“…Regarding the optical properties of TiO 2 , it has been determined that the refractive indexes for rutile and anatase phases are 2.7 and 2.5, respectively [50]. The values of index refraction for TiO 2 are associated with the oxidized metals with the ability to scatter photons.…”

“…The values of index refraction for TiO 2 are associated with the oxidized metals with the ability to scatter photons. Therefore, the rutile reflects light more efficiently [50,52]. However, the most remarkable property of TiO 2 is its ability to absorb light in the ultraviolet (UV) region, which is approximately 4% of the solar spectrum [53][54][55].…”

Titanium dioxide effect on bacteriolytic activity and intrinsic fluorescence of lysozyme

“…TiO 2 входит в топ-5 наиболее часто употребляемых перорально наночастиц (НЧ), которые обладают высокой реактогенностью вследствие запуска окислительного стресса [11,12]. Этот механизм подтверждается увеличением продукции активных форм кислорода, продуктов окисления и истощением клеточных антиоксидантов после воздействия НЧ [12,13].…”

“…Если пероральное потребление наноформ TiO 2 постоянное и высокое (расчетное суточное поступление достигает 1-3 мг/кг массы тела), он может накапливаться в тканях и вызывать необратимые повреждения. Существует множество экспериментальных переменных, которые могут повлиять на результаты анализов токсичности при приеме внутрь, но основными из них являются концентрация и реакционная способность НЧ TiO 2 [13].…”